How Long Does Weed Stay In Your Blood & Urine?

How Long Does Weed Stay In Your System

If you’re planning on driving after using weed or if you work in a company that carries out drug testing, you’re probably looking for an answer to the question “how long does weed stay in your blood & urine?”

Unfortunately, there isn’t a simple one-size-fits-all answer to that question. Weed can be detected in your bodily fluids for between 1 and 30 days following your last use, depending on which testing method is being used, how much you’ve used, and how frequently you’ve used it. In fact, if hair testing is the method of choice, you could find that it remains detectable for a number of months. In general, however, the more often you use weed and the larger the amount you use, the longer the detection time will be. If you’re a daily user, you can expect your weed use to be detectable for a number of months following your final use when the hair testing method is used. In fact, some detection times have been reported of over 90 days.

Luckily, however, hair testing isn’t used very frequently as a detection method. Other options are much more common including urine, blood, and saliva tests. All drug tests for weed aren’t just measuring the weed itself, they’re measuring metabolites – a by-product of marijuana. These stay in the system for a long time even after the effect of the drug has worn off. To be sure how much weed is actually in your system, make sure you're familiar with the metrics of weed - for example, you should know how many grams are in an ounce of weed

Here we look at all the different testing scenarios that you might encounter so you can have the best idea of how long weed stays in your system.

Urine Tests For Weed

If you are urine tested for weed, you can expect it to be detectable for over 30 days if you’re a heavy chronic user. If you use weed on a daily basis, you can expect it to be detected for up to 15 days, whereas if you use up to 4 times per week, you can expect up to 7 days of detection. Occasionally users of 3 times a week or less can expect their use to be detected for up to 3 days following their last use. Since this testing method is the most common option used, especially by employers, this information is very important to know.

How long does weed stay in your system? (Type of test) Type of User How long will weed be detectable in my system
Urine Test daily user (everyday)  Up to 15 days
Urine Test chronic user (4 times per week) Up to 7 days
Urine Test semi-chronic user (3 times per week) Up to 3 days

Blood Tests for Weed

Usually, weed can be detected in your blood for up to two days, however in a few cases, it has been reported as being detectable after 25 days in chronic, heavy users. Weed can be detected in your blood within just a few seconds of use since it is instantly distributed around the body tissues with some being reabsorbed into the blood before being broken down. Metabolites can stay in your bloodstream for several days.

In fact, when thinking about how long weed stays in your blood, check out this chart for a comparison. Weed is in your blood for far longer than many other drugs.


How Long Does Weed Stay In Your System Blood

Saliva Drug Test for Weed:

How long does weed stay in your saliva? One of the more common ways (although not most common) to get tested is done via a saliva drug test. Saliva testing is most commonly used by the police at the roadside when drug-driving offenses are suspected. Weed can be detected in saliva in chronic users for up to 29 days, whereas in occasional users it can be detected for up to three days. 

One thing to keep in mind for drug tests that involve saliva and weed is that the tools that they typically use look like this:


Saliva Drug Test

Hair Drug Test for Weed 

A hair follicle test for weed can assess your use of the drug for as long as 90 days following your last use. Marijuana will reach your hair follicles through tiny blood vessels and trace amounts stay in your hair for a long time. Hair only grows at around half an inch a month, and a 1 1/2 “ segment of hair from close to your scalp provides evidence of weed use during the last 3 months.


Type of Test How long does weed stay in your system? 
Urine Drug Test Up to 15 Days
Blood Drug Test Up to 25 Days
Saliva Drug Test Up to 29 days
Hair Drug Test Up to 90 days


Frequently Asked Questions:

How long will weed take to metabolize?


Weed Metabolism Stay in your system

The psychoactive ingredient in cannabis is THC (or delta-9-tetrahydrocannabinol). When it enters the body, it gets absorbed into your bloodstream. The fatty tissues and organs in the body temporarily store some of the THC and when it is stored in your kidneys it can then be reabsorbed back into your bloodstream. Your liver is responsible for breaking down the THC. There are over 80 different metabolites and drug tests are looking for these since they are capable of staying in the system for longer than the THC itself. Eventually, both the THC and metabolites will be excreted through your stools and feces, but the length of time this process will take will depend on several factors. You should have a sense of how much weed is actually in your body, if you're unsure, make sure you determine how much is in your body by having a weed scale handy. 

Your BMI, your gender and your age will all affect the way in which your body can process and metabolize weed. However, there are some other factors which relate to the drug itself. How frequently and how much weed you use will make a difference to the length of time taken to eliminate the marijuana from your system. If you’re a heavy, frequent user, it’ll take longer to metabolize. Also, if you use weed with a higher THC content, it could remain in your body for longer. Ingesting weed rather than smoking it may also cause a longer metabolizing process.

Is there a way to metabolize weed quickly? 

Unfortunately, there isn’t a lot you can do yourself to metabolize weed any more quickly. After it’s entered your body, it takes some time to break the THC down. Staying properly hydrated, eating healthy foods and taking plenty of exercise can help a little, but not a lot. If you search for weed detox kits and remedies online, you’ll probably find quite a few different options. These herbal supplements are supposed to mask urine that has been diluted with lots of water, however they’re not very reliable.

How long does weed affect your body? 

    The effects from using weed will appear rapidly within 15-30 minutes of smoking or 1-2 hours if ingesting weed. THC, the psychoactive ingredient, makes you feel “high” with common effects including:

    • Feeling relaxed and positive
    • Altered sensory and time perception
    • Chattiness and giggling
    • Lack of focus and coordination
    • Increased appetite and sleepiness
    • Fast heart beat
    • Dry eyes and mouth
    • Restlessness and confusion
    • Feeling faint or sick
    • Paranoia or anxiety

      Although many of the effects that weed produces wear off after a couple of hours, some of the effects such as insomnia may last for several days. If you’re a regular, heavy user the effects may last longer. Some users report effects lasting for several weeks or even months following their final use.

      Final thoughts on "how long does weed stay in your system"? 

      Weed can remain in your system for days or even months following your final use and it can be detected for a considerable period of time depending on which test method is being used as well as how much and how often you use cannabis. Since there isn’t a reliable way to get weed out of your system quickly, you need to take care if you’re likely to be subject to testing.

      Written by